Sheet feeding apparatus, and image forming apparatus, image reading apparatus and communication apparatus using the sheet feeding apparatus

ABSTRACT

An object of the invention is to provide a sheet feeding apparatus of a simple structure which is capable of stacking discharged sheets in a discharged-sheet stacker in an aligned manner without performing any complicated operation even when the sheet size is changed. The common sheet guide is removably attached to the cassette and comes in contact with the sheets stacked in the cassette and the sheets stacked in the stacker. When the sheets in the cassette are replaced with sheets of a different size, as the common sheet guide is moved to come in contact with the edges of the sheets, the common sheet guide is located at the position capable of coming in contact with the edges of the sheets stacked in the stacker. Therefore, it is possible to restrict the movement of the sheets stacked in the stacker and to align the sheets with each other.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a sheet feeding apparatus which stacks a plurality of sheets such as cut sheets of paper, transports the sheets one by one, and stacks the sheets after processing. More particularly, the present invention relates to a sheet feeding apparatus for use in an image forming apparatus of the electrophotographic recording type or the thermal transfer type for example, an image reading apparatus, or a communication apparatus such as a facsimile apparatus.

[0003] 2. Description of the Related Art

[0004]FIG. 4 is a sectional view showing the basic structure of an electrophotographic facsimile apparatus utilizing a prior art sheet feeding apparatus. A plurality of sheets 87 stacked in a sheet cassette 80 as a feed sheet stacking section are picked up one by one by a pickup roller 111 for successive transportation to a transfer section 19. Then, a toner image is transferred to each of the sheets 87 transported to the transfer section 19. The toner image on the sheet 87 is fixed by a fixing roller 120. The sheets 87 onto which images are thus fixed are discharged and stacked in a discharged-sheet stacker 88 which is a discharged-sheet stacking section. The sheet cassette 80 and the discharged-sheet stacker 88 are separately provided. The sheet cassette 80 maybe replaced according to the size of sheets, or may be provided with unillustrated movable guides respectively extending lengthwise and widthwise of sheets for fitting to the size of sheets. In this sheet feeding apparatus 3, for the purpose of stacking sheets 87 of various sizes, the discharged sheet stacker 88 for stacking discharged sheets is not provided with a member such as a guide (stopper) which restricts the movement of the sheets 87.

[0005] The sheet feeding apparatus 3 may be used not only for an image forming apparatus such as a facsimile apparatus but also for an image reading apparatus such as a scanner. Specifically, sheets stacked in the sheet feed stacking section are picked up one by one for reading images formed thereon and then discharged to be stacked in the discharged-sheet stacking section.

[0006] An example of such prior art sheet feeding apparatus is disclosed in Japanese Unexamined Patent Publication JP-A 7-149452 (1995). This sheet feeding apparatus includes a plurality of sheet cassettes correspondingly to the sizes of sheets. One of the plurality of sheet cassettes is upwardly provided with a cassette lid serving as a discharged-sheet stacking section. The sheets discharged from a recording section are stacked on the cassette lid. When the sheet cassette provided with the cassette lid is not attached to the apparatus body of the sheet feeding apparatus, a controller stops the discharging of sheets to prevent the dropping of the sheets and the sheet jam during the discharging.

[0007] To stack the sheets after printing or reading and to satisfactorily align the stacked sheets is an important issue which may influence the subsequent processing for the sheets. However, since the prior art sheet feeding apparatus is not provided with a guide for restricting the movement of the sheets, the discharged sheets freely move on the discharged-sheet stacking section, so that the stacking positions of the sheets do not coincide with each other. Moreover, the stacked sheets may often drop from the discharged-sheet stacking section due to the pushing force of the following sheets.

[0008] For preventing the sheets 87 from dropping, a guide may be provided. Specifically, a guide which is so designed as to correspond to the largest size of sheets among various sizes which can be dealt with may be fixedly attached to the discharged-sheet stacker 88. In this case, the provision of the guide prevents the dropping of the sheets 87. However, when the sheets having a smaller size are used, the sheets stacked on the discharged-sheet stacking section cannot be controlled and aligned, similarly to the case where the guide is not provided. Therefore, the discharged sheets are stacked unacceptably irregularly, so that the sheets need be manually aligned after the printing.

[0009] Japanese Unexamined Patent Publication JP-A 10-218466 (1998) discloses a sheet feeding apparatus provided with a guide for restricting the movement of discharged sheets. This sheet feeding apparatus performs restriction of front edges of documents in discharging the documents. Specifically, the document tray includes a plurality of discharged-document stoppers (guides) provided correspondingly to the sizes of documents and arranged along the document transport direction. Each of the discharged-document stoppers is movable between a restriction position for engaging with the front edges of the discharged documents and a retreated position for retreating from the front edges of the discharged documents.

[0010] In this apparatus, the discharged-document stoppers, which corresponds to the size of documents, is moved to the restriction position by a driving motor for stacking the documents in an aligned manner. Therefore, the structure for moving the discharged-document stopper is complicated, which disadvantageously increases the manufacturing cost. Moreover, to operate selected one of the plural discharged-document stoppers, the work for inputting the document size by the operator or means for detecting the document size is required. Thus, in the case where the operator inputs the document size, the operation efficiency is deteriorated, whereas, in the case where the detection means is provided, the structure becomes more complicated.

[0011] Another prior art sheet feeding apparatus which utilizes a guide having a more simple structure than the above is disclosed in Japanese Unexamined Patent Publication JP-A 6-144598 (1994), for example. FIG. 5A is a perspective view showing the image forming apparatus having the simply structured guide, and FIG. 5B is a sectional view showing the sheet cassette of the image forming apparatus of FIG. 5A.

[0012] In the image forming apparatus 50, the sheet cassette 70 is removably attached to an apparatus body 60 where image forming is performed. The sheet cassette 70 stores sheets 56 on which images are to be formed. The sheet cassette 70 includes a cassette body 51 attached to the apparatus body 60, a slide portion 52, a slide lid 53 and a stopper 54. The slide portion 52 is slidably attached to the cassette body 51. The sheets 56 are so stacked as to locate on both of the slide portion 52 and the cassette body 51. Specifically, with respect to each of the sheets 56 stacked in the sheet cassette 70, the longitudinally front half of the sheet is supported by the bottom plate of the cassette body 51, whereas the rear half of the sheet is supported by the bottom plate of the slide portion 52, for example. By moving the slide portion 52 in a sliding manner toward or away from the apparatus body 60, the cassette body 51 can be freely expanded or contracted, so that sheets 56 of various sizes can be stored in the sheet cassette 70.

[0013] The slide lid 53 is attached so as to cover an upper portion of the slide portion 52. The slide lid 53 is removably attached to the slide portion 52. The slide lid 53 moves relative to the apparatus body 60 together with the sliding movement of the slide portion 52. The sheets 56 fed from the sheet cassette 70 into the apparatus body 60 are discharged onto the slide lid 53. The slide lid 53 is provided with the stopper 54 for preventing the discharged sheets 56 from moving due to the discharging force. Thus, the discharged sheets 56 hit against the stopper 54 so that the movement is restricted.

[0014] In the prior art sheet feeding apparatus 50 shown in FIGS. 5A and 5B, when the slide portion 52 is slid, the sheet 56 rubs against the bottom plate of the slide portion 52. As a result, the sheet 56 may be stained or folded, which may lead to transport failure. Further, since the respective front halves of the sheets 56 are stacked on the bottom plate of the cassette body 51 whereas the respective rear halves are stacked on the bottom plate of the slide portion 52, a large load is exerted on the slide portion, which increases the likelihood of breakage of the slide portion 52.

SUMMARY OF THE INVENTION

[0015] It is, therefore, an object of the present invention to provide a sheet feeding apparatus of a simple structure which is capable of feeding sheets while preventing damage to the sheets and transport failure and which is also capable of stacking discharged sheets in a discharge tray as aligned even when sheets are replaced with those having a different size.

[0016] The present invention provides a sheet feeding apparatus comprising: an apparatus body for inserting sheets fed thereto and discharging the sheets; a feed sheet stacking section, mounted to the apparatus body, for stacking sheets to be fed to the apparatus body; and a discharged-sheet stacking section, mounted to the apparatus body, for stacking sheets discharged from the apparatus body,

[0017] wherein the feed sheet stacking section includes a feed sheet stack plate on which the sheets to be fed are stacked so that an almost entire bottom surface of the stack of the sheets is supported by the feed sheet stack plate,

[0018] the discharged-sheet stacking section includes a discharged-sheet stack plate which extends substantially parallel to the feed sheet stack plate and on which the discharged sheets are stacked so that an almost entire bottom surface of the stack of the sheets is supported by the discharged-sheet stack plate, and

[0019] a common sheet guide is provided on an upstream side from the feed sheet stack plate in a sheet insert direction and on a downstream side from the discharged-sheet stack plate in a sheet discharge direction, the common sheet guide being movable in the sheet insert direction and the sheet discharge direction, for guiding sheets by coming in contact with edges of the sheets stacked in the feed sheet stacking section and edges of the sheets stacked in the discharged-sheet stacking section.

[0020] According to the present invention, since the common sheet guide comes in contact with the sheets stacked in the feed sheet stacking section and the sheets stacked in the discharged-sheet stacking section, the movement of each sheet can be restricted so that the sheets can be aligned with each other. Further, the common sheet guide is movably provided. Therefore, by appropriately moving the common sheet guide, when the sheets to be stacked in each stacking section are replaced with sheets having another size, it is possible to stack the sheets so as to align them.

[0021] Further, since the feed sheet stack plate and the discharged-sheet stack plate extend substantially parallel to each other and the common sheet guide is arranged on the upstream side from the feed sheet stack plate in the sheet insert direction and on the downstream side from the discharged-sheet stack plate in the sheet discharge direction, it is possible to collectively restrict the movement of the sheets stacked in the feed sheet stacking section and the sheets stacked in the discharged-sheet stacking section.

[0022] For example, in the case where the sheets stored in the feed sheet stacking section are replaced with sheets having a different size from those of the initially stored sheets, the common sheet guide can be moved to an appropriate position by bringing the common sheet guide into contact with the newly inserted sheets, thereby aligning the sheets stacked in the feed sheet stacking section. At this time, the common sheet guide is moved to the restriction position for restricting the movement of the sheets stacked in the discharged-sheet stacking section and comes in contact with the downstream edges in the sheet discharge direction of the sheets stacked in the discharged-sheet stacking section.

[0023] Thus, just by bringing the common sheet guide into contact with the sheets stored in the feed sheet stacking section, the sheets in the discharged sheet stacking section can be aligned without conducting any special operation. Further, the common sheet guide can be composed of a single movable member and can be easily located at a proper position by the sheet supplier in accordance with the size of the sheets. Therefore, means for driving the common sheet guide and means for detecting the sheet size need not be provided, so that the sheet feeding apparatus can be have a simple structure and the number of structural parts can be reduced. Accordingly, the sheet feeding apparatus can be inexpensively manufactured and can have the function of aligning sheets without increasing the manufacturing cost.

[0024] Further, the almost entire bottom surface of the stack of the sheets is supported by each of the stackplates. Therefore, unlike the prior art apparatus which utilizes a slide member, damage to the sheets due to the movement of the guide can be prevented. By preventing damage to the sheets, failure in transporting the sheets can also be prevented.

[0025] Further, in the invention it is preferable that the feed sheet stacking section and the discharged-sheet stacking section are arranged at an upper position or a lower position relative to each other, the sheet stacking section arranged at the upper position is mounted so as to be angularly displaced relative to the sheet stacking section arranged at the lower position, thereby enabling supply and removal of sheets relative to the sheet stacking section arranged at the lower position.

[0026] According to the present invention, by the angular displacement of the upper one of the sheet stacking sections, the space between the upper sheet stacking section and the lower sheet stacking section can be increased. Therefore, the supply and removal of sheets can be easily performed without detaching the upper sheet stacking section from the apparatus body.

[0027] Further, in the invention it is preferable that the feed sheet stacking section and the discharged-sheet stacking section are arranged at an upper position or a lower position relative to each other, at least one of the sheet stacking sections being mounted to the apparatus body so as to be capable of being pulled out from the apparatus body, thereby enabling supply and removal of sheets relative to the sheet stacking section arranged at the lower position.

[0028] According to the invention, at least one of the feed sheet stacking section and the discharged-sheet stacking section is mounted to the apparatus body so as to be capable of being pulled out from the apparatus body. Therefore, by pulling out the at least one sheet stacking section from the apparatus body, the upside of the lower stacking section can be made open, and thereby the supply and removal of sheets can be easily performed.

[0029] Further, the invention provides an image forming apparatus which utilizes the above-described sheet feeding apparatus.

[0030] Furthermore, the invention provides an image reading apparatus which utilizes the above-described sheet feeding apparatus.

[0031] Further, the invention provides a communication apparatus which utilizes the above-described sheet feeding apparatus.

[0032] According to the invention, the image forming apparatus may be, for example, a copying machine or a printer. The image reading apparatus may be, for example, a copying machine or a scanner. The communication apparatus may be, for example, a facsimile apparatus. By utilizing the above-described sheet feeding apparatus for these apparatuses, it is possible to feed sheets stacked in the feed sheet stacking section and to stack discharged sheet in the discharged-sheet stacking section. Since the sheets discharged to the discharged-sheet stacking section are stacked so as to be aligned with each other, the troublesome work of manually aligning the sheets can be eliminated, which enhances the convenience.

[0033] According to the present invention, in storing sheets in the feed sheet stacking section, when the common sheet guide is placed at the restriction position for aligning sheets stacked in the feed sheet stacking section, the common sheet guide is also placed at the restriction position for the discharged-sheet stacking section in accordance with the size of the sheets stored in the feed sheet stacking section. Therefore, without performing any special work, the sheets discharged to the discharged-sheet stacking section can be controlled and aligned by the common sheet guide. Further, even when a sheet size is changed, the work for manually aligning the sheets can be eliminated. This facilitates the processing after the discharging of the sheets.

[0034] Moreover, the sheet feeding apparatus can have a simple structure and the number of structural parts can be reduced. Accordingly, the sheet feeding apparatus can be inexpensively manufactured and can have the function of aligning sheets without increasing the manufacturing cost.

[0035] According to the invention, the supply and removal of sheets can be easily performed without detaching the sheet stacking section arranged at the upper position from the apparatus body. Therefore, time is not spent for detaching the upper sheet stacking section, which makes it possible to supply and remove sheets in a short time.

[0036] According to the invention, at least one of the feed sheet stacking section and the discharged-sheet stacking section is mounted to the apparatus body so as to be capable of being pulled out from the apparatus body. Therefore, by pulling out the at least one sheet stacking section from the apparatus body, the upside of the lower stacking section can be made open, and thereby sheets can be easily performed supplied to or removed from the sheet stacking section arranged at the lower position.

[0037] According to the invention, by utilizing the above-described sheet feeding apparatus for an image forming apparatus, an image reading apparatus or a communication apparatus, sheets can be stacked in the discharged-sheet stacking section in an aligned manner even when the sheet size is changed. Thus, the sheets need not be manually aligned, which makes it possible to easily carry out the following work and to provide enhanced convenience.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein:

[0039]FIG. 1 is a sectional view showing a sheet feeding apparatus according to an embodiment of the present invention as enlarged;

[0040]FIG. 2 is a sectional view showing the basic structure of a laser facsimile apparatus utilizing the sheet feeding apparatus of FIG. 1;

[0041]FIG. 3 is a sectional view showing a sheet feeding apparatus according to another embodiment of the present invention as enlarged;

[0042]FIG. 4 is a sectional view showing the basic structure of a laser facsimile apparatus utilizing a prior art sheet feeding apparatus; and

[0043]FIGS. 5A and 5B illustrate an image forming apparatus utilizing another prior art sheet feeding apparatus, where FIG. 5A is a perspective view showing the image forming apparatus and FIG. 5B is a sectional view showing the prior art sheet cassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Now referring to the drawings, preferred embodiments of the invention are described below.

[0045]FIG. 1 is a sectional view showing a sheet feeding apparatus according to an embodiment of the present invention as enlarged. FIG. 2 is a sectional view showing the basic structure of a laser facsimile apparatus utilizing the sheet feeding apparatus of FIG. 1. The laser facsimile apparatus 2 prints a read image on a sheet supplied thereto and then discharges the sheet.

[0046] As shown in FIG. 2, the laser facsimile apparatus 2 includes an operation section 11. The operation section 11 is provided with various keys for inputting information by the operator, and a display for providing information for the operator, thereby serving as a man-machine interface. For example, by operating the operation section 11, the operator can give the laser facsimile apparatus 2 an instruction to read an image of a document.

[0047] Plural sheets of documents formed with images to be read are disposed on a document feeder 12 provided above an apparatus body 6. When an image-read instruction is given, the documents are fed, one by one, to an image reading unit 113 by a separator roller 13, and the image on each of the documents is read. After the image is read, the document is transported by a document discharge roller 115 for discharge to a document discharge section 114. The document discharge section 114 is provided with a document stacker (not shown) for stacking the documents whose images have been read.

[0048] The sheet feeding apparatus 1 for feeding sheets 117 on which images are to be formed is arranged at a lower portion of the laser facsimile apparatus 2. The sheet feeding apparatus 1 comprises the apparatus body 6 including a pickup roller 111 for transporting the sheets 117 and a record transport roller (not shown), a sheet cassette 110 and a discharged-sheet stacker 118 both of which are arranged adjacent the apparatus body 6. The sheet cassette 110, which is a feed sheet stacking section, stores a plurality of sheets 117 as stacked. The staked sheets 117 are picked up one by one by the pickup roller 111 for transportation to a transfer section 19. In the transfer section 19, a toner image, which is a visible image formed on a photosensitive drum 18, is transferred to each of the sheets 117. The sheet 117 is then transported to a fixing roller 120 and pressed against the fixing roller 120 at a high temperature, so that the toner image is fused and fixed onto the sheet 117. The sheets 117 on which images are thus fixed are successively stacked in a discharged-sheet stacker 118 which is a discharged-sheet stacking section. In this way, the sheets 117 travels along a sheet travel route 116 extending along the above-described path. For purpose of avoiding complexity and simple illustration, such means as a guide or a roller for transporting the sheets 117 along the sheet travel route 116 is not illustrated in FIG. 2.

[0049] The printing on each of the sheets 117 is performed as follows. First,the photosensitive drum 18 is charged at a charge section 112. Then, a laser beam 16 from a laser unit 15 is applied to the photosensitive drum 18. Specifically, the laser beam 16 is modulated in accordance with the information to be printed, and becomes, by a non-illustrated polygon mirror, a scanning light for scanning the photosensitive drum 18 over a width corresponding to the sheet width. The laser beam 16 emitted from the laser unit 15 is reflected by reflective mirrors 14 to be directed to the photosensitive drum 18. At this time, the laser beam 16 is in the form of an ON/OFF pattern necessary for the image printing. The surface potential of the photosensitive drum 18 charged at the charge section 112 lowers at portions irradiated with the laser beam. Thus, an electrostatic latent image corresponding to the image to be printed is formed on the photosensitive drum 18.

[0050] Then, in a developer unit 17, toner particles adhere to the photosensitive drum 18 in accordance with the electrostatic latent image, forming a visible toner image. As described before, the visible image is transferred to the sheet 117 at the transfer section 19.

[0051] The sheet feeding apparatus 1 will be described below in detail. As shown in FIG. 1, the sheet feeding apparatus 1 is provided with the apparatus body 6 where sheets 117 are transported, the sheet cassette 110, the discharged-sheet stacker 118 and a common sheet guide 119. By the pickup roller 111, the sheets 117 are inserted along the insert direction indicated by the arrow A into the image forming apparatus and then make a U-turn to be discharged in the discharge direction indicated by the arrow B.

[0052] The sheet cassette 110 includes a rectangular feed sheet stack plate 110 a, a press member 131 and a spring 130. The sheets 117 to be fed to the apparatus body 6 are stacked on the feed sheet stack plate 110 a so that an almost entire bottom surface of the stack of sheets is supported by the feed sheet stack plate. The feed sheet stack plate 110 a includes a feed-side edge 110 b rising from the end closer to the apparatus body 6. The sheet cassette 110 is removably attached to the apparatus body 6 arranged substantially horizontally. When the sheet cassette 110 is attached to the apparatus body 6, the feed sheet stack plate 110 a is held substantially horizontally. The press member 131 together with the spring 130 resiliently supports the almost entire bottom surface of the stack of the sheets 117 stacked on the feed sheet stack plate 110 a so as to bias the stack of the sheets 117 upward toward the pickup roller 111. For example, the press member 131 biases the sheets upward while keeping the horizontal posture of the sheets. The sheets 117 biased upward are picked up one by one by the pickup roller 111 and transported.

[0053] The discharged-sheet stacker 118, which is arranged above the sheet cassette 110, includes a rectangular discharged-sheet stack plate 118 a and a discharged-sheet stacker handle 32. The sheets 117 discharged from the apparatus body 6 are stacked on the discharged-sheet stack plate 118 a so that an almost entire bottom surface of the stack of the sheets is supported by the discharged-sheet stack plate. The discharged-sheet stack plate 118 a includes a discharge-side edge 118 b rising from the end closer to the apparatus body 6. The discharged-sheet stacker 118 is attached to the apparatus body 6 so that the discharged-sheet stack plate 118 a is held generally in parallel to the feed sheet stack plate 110 a. The discharged-sheet stacker 118 is arranged above the sheet cassette 110 and at a position deviated from the sheet cassette 110 in the discharge direction B relative to the apparatus body 6.

[0054] The common sheet guide 119 is attached to the sheet cassette 110 and the discharged-sheet stacker 118. The common sheet guide 119 is arranged adjacent the end of the feed sheet stack plate 110 a on the upstream side in the insert direction and adjacent the end of the discharged-sheet stack plate 118 a on the downstream side in the discharge direction. The common sheet guide 119 is movable in the insert direction A and in the discharge direction B.

[0055] The common sheet guide 119 includes a feed-side contact plate 119 a and a discharge-side contact plate 119 b. The feed-side contact plate 119 a comes in contact with respective rear edges (the upstream edges in the sheet insert direction A) of the sheets 117 stacked in the sheet cassette 110. The discharge-side contact plate 119 b comes in contact with respective front edges (the downstream edges in the sheet discharge direction B) of the sheets 117 stacked in the discharged-sheet stacker 118.

[0056] Since the common sheet guide 119 comes in contact with the sheets 117 stacked in the sheet cassette 110 and the sheets 117 stacked in the discharged-sheet stacker 118, the movement of the sheets 117 discharged to the discharged-sheet stacker 118 can be restricted, thereby the sheets 117 can be aligned with each other.

[0057] In this embodiment, the sheet cassette 110 is arranged at a position deviated from the discharged-sheet stacker 118 in the sheet insert direction, as described above. For conformity to this arrangement, the common sheet guide 119 has a stepped configuration. Specifically, the common sheet guide 119 comprises four plate members 119 a, 119 b, 119 c and 119 d adjacent ones of which are connected perpendicularly to each other at respective ends. The slide plate 119 c of the common sheet guide 119 is attached to the lower surface of the sheet cassette 110 movably relative to the sheet cassette 110. The feed-side contact plate 119 a is connected to the slide plate 119 c. The discharge-side contact plate 119 b is connected to the feed-side contact plate 119 a via the adjustment plate 119 d attached to the lower surface of the discharged-sheet stacker 118.

[0058] The common sheet guide is so arranged that the length of the adjustment plate 119 d equals to the deviation amount of the sheet cassette 110 relative to the discharged-sheet stacker 118 in the insert direction A. Therefore, when the feed-side contact plate 119 a is brought into contact with the edges of the sheets 117 stacked in the sheet cassette 110, the discharge-side contact plate 119 b is brought into contact with the edges of the sheets 117 stacked in the discharged-sheet stacker 118.

[0059] For example, in the case where the sheets 117 stored in the sheet cassette 110 are replaced with sheets 117 having a different size from those of the initially stored sheets 117, the common sheet guide 119 can be moved to a proper position by bringing the common sheet guide 119 into contact with the newly inserted sheets 117, thereby aligning the sheets 117 stacked in the sheet cassette 110. At this time, the common restriction guide 119 is moved to the position for restricting the movement of the sheets 117 stacked in the discharged-sheet stacker 118 and comes in contact with the downstream edges in the sheet discharge direction of the sheets 117 stacked in the discharged-sheet stacker 118. Thus, just by bringing the common sheet guide plate 119 into contact with the sheets 117 newly supplied in the sheet cassette 110, the sheets 117 in the discharged-sheet stacker 118 can be aligned without conducting any special operation.

[0060] The common sheet guide 119 can be composed of a single movable member and can be easily located at a proper position by sheet supplier in accordance with the size of the sheets. Therefore, means for driving the common sheet guide 119 and means for detecting the sheet size need not be provided, so that the sheet feeding apparatus 1 can be have a simple structure and the number of structural parts can be reduced.

[0061] Further, since the common sheet guide 119 is movable in the insert direction A and in the discharge direction B, sheets 117 having a different size can be placed without the need for replacing the sheet cassette 110 with another one. Furthermore, the sheets 117 can be stacked in the discharged-sheet stacker 118 in an aligned manner without conducting any complicated operation.

[0062] The discharged-sheet stacker 118 is provided with a discharged-sheet stacker rotary shaft 31 which angularly displaceably supports the discharged-sheet stacker 118 to the sheet cassette 110 and the discharged-sheet stacker handle 32. The rotary shaft 31, extending in parallel with a horizontal plane and substantially perpendicularly to the discharge direction B, is arranged at the upstream end 123 in the sheet discharge direction B of the discharged-sheet stacker 118. With this arrangement, the discharged-sheet stacker 118 is angularly displaceable about the axis of the rotary shaft 31. In other words, the discharged-sheet stacker 118 is angularly displaceably arranged so that the down stream end in the sheet discharge direction B of the discharged-sheet stacker 118 is kept away from or close to the sheet cassette 110. When the discharged-sheet stacker 118 is angularly displaced in the direction C for raising the downstream end 124 in the sheet discharge direction B of the discharged-sheet stacker 118, the space between the discharged-sheet stacker 118 and the sheet cassette 110 is increased at the downstream side in the sheet discharge direction B. The discharged-sheet stacker handle 32 is arranged at the downstream side 124 in the sheet discharge direction B. Just by raising the stacker handle 32 by the user, the discharged-sheet stacker 118 can be easily angularly displaced.

[0063] Although the discharged-sheet stacker 118 is so arranged as to cover the sheet cassette 110 and supply of the sheet 117 to the sheet cassette 110 may be apparently difficult, the discharged-sheet stacker 118 can be angularly displaced as described above. Therefore, the supply and removal of sheets 117 can be easily performed utilizing the increased space between the sheet cassette 110 and the discharged-sheet stacker 118 without the need for detaching the discharged-sheet stacker 118 from the apparatus body 6. Moreover, since the discharged-sheet stacker 118 is angularly displaced about the upstream end 123 in the sheet discharge direction, the upstream end 123 does not largely separate from the apparatus body 6 even when the space is increased. Therefore, it is possible to increase the space and to supply and remove sheets 117 without preventing the discharge of the sheets 117.

[0064] Although the discharged-sheet stacker 118 is angularly displaced in a raising manner in this embodiment, the discharged sheet stacker 118 may be horizontally moved in the angular displacement direction, or laterally about the apparatus body 6. In other words, the discharged-sheet stacker 118 may be angularly displaced about the axis perpendicular to the horizontal plane. Alternatively, as shown in FIG. 3 showing a view of a sheet feeding apparatus 1 a of another embodiment of the invention, the discharged-sheet stacker 118 may be pulled in the discharge direction B. By such movement, sheets 117 can be easily supplied to or removed from the sheet cassette 110 disposed below the discharged-sheet stacker.

[0065] Moreover, in this embodiment, the sheets 117 are discharged through the fixing roller 120 to drop onto the discharged-sheet stacker 118. On the discharged-sheet stacker 118, the movement of the sheets 117 is restricted by both of the discharge-side contact plate 119 b of the common sheet guide 119 and the discharge-side edge 118 b of the discharged-sheet stack plate 118 a. Therefore, as compared with the case where the sheets are aligned only by the discharge-side contact plate 119 b, the sheets 117 can be more precisely aligned.

[0066] Further, the sheet cassette 110, the sheets 117 are stacked so that the almost entire bottom surface of the stack sheets 117 is supported by the feed sheet stack plate 110 a of the sheet cassette 110 and are not stacked on the common sheet guide 119. Therefore, unlike the prior art apparatus which utilizes a slide member, the movement of the guide does not cause the sheet 117 to be stained or folded. Since such damage to the sheet 117 can be prevented, the transport failure of the sheet can also be prevented. Moreover, since the press member 131 biases the sheets 117 upward while keeping the horizontal posture of the sheets, the sheets 117 can be prevented from bending.

[0067] The above-described structure is merely an example of the present invention and may be modified in various ways without departing from the scope of the invention. For example, although the discharged-sheet stacker 118 is arranged as deviated downstream in the discharge direction relative to the sheet cassette 110, this positional relationship is not limitative of the present invention.

[0068] Further, in the above-described embodiment, the common sheet guide 119 is movable in the sheet insert direction A and the sheet discharge direction B. However, the sheet feeding apparatus 1 may further include another common sheet guide which is movable in a direction perpendicular to the sheet insert direction A and the sheet discharge direction B within a horizontal plane. With such an arrangement, the sheets 117 discharged can be aligned both in the longitudinal direction and in the widthwise direction.

[0069] Moreover, the feed sheet stack plate 110 a and the discharged-sheet stack plate 118 a may be inclined relative to the horizontal surface as long as they extend generally parallel to each other. In such a case, the common sheet guide may be so arranged as to be movable in the direction in which the feed sheet stack plate 110 a and the discharged-sheet stack plate 118 a extend.

[0070] Hereinabove, as an example of the invention, reference is made to the sheet feeding apparatus 1, used in the facsimile apparatus, for transporting sheets. However, the sheet feeding apparatus is applicable to any apparatus having a structure for feeding and discharging sheets. For example, the sheet feeding apparatus of the invention is applicable to a communication apparatus such as a facsimile apparatus, an image forming apparatus such as a copying machine or a printer, an image reading apparatus such as a scanner, or an information processing apparatus integrally provided with a printer, providing the same advantages as the above.

[0071] Further, sheets used for the embodiment may not be sheets of paper but may be, for example, resin sheets for use with an OHP (overhead projector).

[0072] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein. 

What is claimed is:
 1. A sheet feeding apparatus comprising: an apparatus body for inserting sheets fed thereto and discharging the sheets; a feed sheet stacking section, mounted to the apparatus body, for stacking sheets to be fed to the apparatus body; and a discharged-sheet stacking section, mounted to the apparatus body, for stacking sheets discharged from the apparatus body, wherein the feed sheet stacking section includes a feed sheet stack plate on which the sheets to be fed are stacked so that an almost entire bottom surface of the stack of the sheets is supported by the feed sheet stack plate, the discharged-sheet stacking section includes a discharged-sheet stack plate which extends substantially parallel to the feed sheet stack plate and on which the discharged sheets are stacked so that an almost entire bottom surface of the stack of the sheets is supported by the discharged-sheet stack plate, and a common sheet guide is provided on an upstream side from the feed sheet stack plate in a sheet insert direction and on a downstream side from the discharged-sheet stack plate in a sheet discharge direction, the common sheet guide being movable in the sheet insert direction and the sheet discharge direction, for guiding sheets by coming in contact with edges of the sheets stacked in the feed sheet stacking section and edges of the sheets stacked in the discharged-sheet stacking section.
 2. The sheet feeding apparatus of claim 1, wherein the feed sheet stacking section and the discharged-sheet stacking section are arranged at an upper position or a lower position relative to each other, the sheet stacking section arranged at the upper position is mounted so as to be angularly displaced relative to the sheet stacking section arranged at the lower position, thereby enabling supply and removal of sheets relative to the sheet stacking section arranged at the lower position.
 3. The sheet feeding apparatus of claim 1, wherein the feed sheet stacking section and the discharged-sheet stacking section are arranged at an upper position or a lower position relative to each other, at least one of the sheet stacking sections being mounted to the apparatus body so as to be capable of being pulled out from the apparatus body, thereby enabling supply and removal of sheets relative to the sheet stacking section arranged at the lower position.
 4. An image forming apparatus which utilizes the sheet feeding apparatus of claim
 1. 5. An image reading apparatus which utilizes the sheet feeding apparatus of claim
 1. 6. A communication apparatus which utilizes the sheet feeding apparatus of claim
 1. 